CHAC1 and chronic kidney disease: Shengqing Jiangzhuo (SQJZ) capsule possesses potential to alleviate CKD via gut-kidney axis, with the specific role and mechanisms involving CHAC glutathione-specific γ-glutamylcyclotransferase 1 (CHAC1) and hypoxia-inducible factor 1 (HIF-1) signaling remaining unclear.